Surgical neutering in ferrets can be done in any ferret over 3 months old. In jills it is most often done just before their first breeding season.
Unlike in cats, dogs and rabbits, surgical neutering of ferrets may make them more likely to develop a condition known as ‘hyperadrenocorticism’ (adrenal gland disease). This is a hormonal condition and can lead to hair loss, weight loss, vulval swelling (jills), itchy skin and hyper-sexuality (even in neutered animals). There is no cure for hyperadrenocorticism, but the condition can be managed, and in some cases changes are only cosmetic.
Surgical neutering does have some pros. Surgical neutering removes the risk of any cancers of the reproductive organs (ovarian, uterine and testicular), and also removes the risk of uterine infection in jills. There is only a single cost, as this is the only permanent option.
Although there are some pros to surgical neutering of ferrets, it is rarely recommended due to the wide availability of the implant, and the risk of developing hyperadrenocorticism.